1. Field of the Invention
The present invention relates to a toner container detachably attached to a developer provided in an apparatus body of an image forming apparatus, and an image forming apparatus provided with the toner container.
2. Description of the Related Art
An electrophotographic image forming apparatus generally has, in the periphery of a photosensitive drum as an image carrier, a charger, an exposure unit, a developer, a transferer, and a cleaner. An electrostatic latent image is formed on the surface of the photosensitive drum by irradiating light representing image information from the exposure unit onto the surface of the photosensitive drum where uniform electric charges are supplied by the charger. Then, the electrostatic latent image is developed into a toner image by supplying toner i.e. toner particles (hereinafter, toner particles are simply called as “toner”) onto the electrostatic latent image by the developer. Then, the toner image is transferred onto a sheet. The sheet carrying the transferred toner image is transported to a fixing device provided downstream of the photosensitive drum, where the toner image is fixed by heating. After the image fixation, the sheet carrying the fixed toner image is discharged outside of the image forming apparatus.
Normally, a toner container is detachably attached to the developer. A toner replenishing port is formed at an appropriate position in a bottom wall of the toner container so that the toner accommodated in the toner container is replenished to the developer through the replenishing port. When the toner in the toner container is reduced to such an amount that toner replenishment to the developer is incapable as a result of developing process, the toner container is replaced with a new toner container filled with toner.
It is often the case that the bottom wall of the toner container is formed into e.g. a funnel-like shape with a slope tilted toward the replenishing port so as to replenish the toner in possible total amount to the developer. The arrangement is proposed based on an expectation that the toner in the toner container may be guided along the slope, and substantially all the toner in the toner container may be replenished to the developer.
Forming the bottom wall into a funnel-like shape, however, not only leads to a reduced capacity of the toner container, but also leads to forming a waste space corresponding to the funnel portion in the apparatus body of the image forming apparatus. As a result, miniaturization of the image forming apparatus may be hindered.
In view of the above, there is proposed an arrangement of forming the bottom wall of the toner container into a horizontally flat plate (see e.g. Japanese Unexamined Patent Publication No. 2002-278424). Forming the bottom wall of the toner container into a flat plate may be advantageous in increasing the capacity of the toner container by the space corresponding to the funnel portion, and in miniaturizing the image forming apparatus.
Forming the bottom wall of the toner container into the flat plate, however, may obstruct guiding the toner toward the replenishing port, which makes is impossible to replenish all the toner in the toner container to the developer. As a result, the toner container is required to be replaced with a new one, despite toner remainder in the toner container. This is waste of toner.
In other words, the conventional toner container has contradictory problems to be solved: forming the bottom wall of the toner container into a funnel-like shape in an attempt to eliminate toner remainder may obstruct miniaturization of the image forming apparatus; and forming the bottom wall into a flat shape in an attempt to miniaturize the image forming apparatus may increase the amount of toner remainder in the toner container.